This invention relates to valves for the control of the flow through conduits of water and other fluids. It pertains particularly to valves of the class including a seal washer provided with means for preventing scuffing of the washer during operation of the valve and with means for preventing contamination of fluid passed by the valve with foreign material inadvertently introduced into the valve chamber. The valve is described herein with particular reference to valves for domestic water lines, although no limitation thereby is intended.
In the dispensing of water through conduits in both domestic and industrial installations, there are many situations where a single source is tapped to divert the water from that source to two or more applications. For example, it may be desired to divert water from a pressurized domestic source to the operation of a kidney dialysis machine. This is usually accomplished by tapping into the pressurized cold water house line which normally feeds also a domestic water outlet.
In a similar manner, it is often the practice to tap into the pressurized house line to supply water for mortuaries, hospitals, laboratories, laundries, chemical processing installations and the like. All of these introduce into possible communication with the domestic tap serious sources of contamination. Examples of such sources are the formaldehyde wash waters used for disinfecting kidney machines; mortuary fluids and wash water; bacteriologically contaminated laboratory solutions; poisonous chemical solutions, etc.
No problem exists as long as a normal pressure is maintained on the house line supplying water under pressure to the installation. However, in the event of failure of the pressurized water source, disconnecting the pressurized line for purposes of installation or repair; or other occurrences, circumstances frequently arise wherein the pressure in the pressurized house line is sharply reduced. A vacuum may even be created. In such occurrences, contaminating fluids may be drawn into the system and subsequently discharged through the domestic tap.
It is the general purpose of the present invention to provide a valve assembly which positively prevents such a result.
It is another object of the present invention to provide a valve assembly for the control of the flow of water through conduits which assembly incorporates a seal washer with associated means for minimizing the wear or scuffing of the washer during operation of the valve.
It is a further object of the present invention to provide a valve assembly which accomplishes the purposes outlined above and which in addition is simple in construction, inexpensive to manufacture, positive in its action, versatile in its application, easy to maintain, and having a long service life.
The foregoing and other objects of this invention are achieved by the provision of a floating, seal valve assembly comprising a casing housing a valve chamber. An inlet port and an outlet port communicate with the valve chamber. A valve seat and valve-operating subassembly are associated with at least one of the ports, preferably the outlet port.
Each valve-operating subassembly comprises an axially bored valve body threaded into the casing adjacent the valve seat. A headed shaft is mounted in the bore. A seal washer is mounted on the head of the shaft.
A coil spring or other resilient means is mounted on the shaft for urging the washer in the direction of engagement with the valve seat with a force less than the force of the pressurized fluid to be introduced into the chamber. The shaft and/or seal washer preferably are rotatably mounted to minimize wear of the washer during use of the valve.
During such use, the pressure of the water from the house line overcomes the force of the spring when the valve is open. The valve then dispenses water in the normal manner. However, in the event of failure of water pressure in the house line, the spring or other resilient means maintains the valve in a closed position so that backup of harmful fluids cannot occur.